Circular economy for plastic waste to polyethylene via refinery FCC feed pretreater and FCC units

ABSTRACT

Provided in one embodiment is a continuous process for converting waste plastic into recycle for polyethylene polymerization. The process comprises selecting waste plastics containing polyethylene and/or polypropylene, and passing the waste plastics through a pyrolysis reactor to thermally crack at least a portion of the polyolefin waste and produce a pyrolyzed effluent. The pyrolyzed effluent is separated into offgas, a pyrolysis oil and optionally pyrolysis wax comprising a naphtha/diesel fraction and heavy fraction, and char. The pyrolysis oil and wax is passed to a refinery FCC feed pretreater unit. A heavy fraction is recovered and sent to a refinery FCC unit, from which a C3 olefin/paraffin mixture fraction is recovered, which is passed to a steam cracker for ethylene production. In another embodiment, a propane fraction (C3) is recovered from a propane/propylene splitter and passed to the steam cracker.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 63/002,053 filed Mar. 30, 2020, the complete disclosure of which isincorporated herein by reference in its entirety.

BACKGROUND

The world has seen extremely rapid growth of plastics production.According to PlasticsEurope Market Research Group, the world plasticsproduction was 335 million tons in 2016, 348 million tons in 2017 and359 million tons in 2018. According to McKinsey & Company, the globalplastics-waste volume was estimated about 260 million tons per year in2016, and projected to be 460 million tons per year by 2030 if thecurrent trajectory continues.

Single use plastic waste has become an increasingly importantenvironmental issue. At the moment, there appear to be few options forrecycling polyethylene and polypropylene waste plastics to value-addedchemical and fuel products. Currently, only a small amount ofpolyethylene and polypropylene is recycled via chemical recycling, whererecycled and cleaned polymer pellets are pyrolyzed in a pyrolysis unitto make fuels (naphtha, diesel), stream cracker feed or slack wax.

Processes are known which convert waste plastic into hydrocarbonlubricants. For example, U.S. Pat. No. 3,845,157 discloses cracking ofwaste or virgin polyolefins to form gaseous products such asethylene/olefin copolymers which are further processed to producesynthetic hydrocarbon lubricants. U.S. Pat. No. 4,642,401 discloses theproduction of liquid hydrocarbons by heating pulverized polyolefin wasteat temperatures of 150-500° C. and pressures of 20-300 bars. U.S. Pat.No. 5,849,964 discloses a process in which waste plastic materials aredepolymerized into a volatile phase and a liquid phase. The volatilephase is separated into a gaseous phase and a condensate. The liquidphase, the condensate and the gaseous phase are refined into liquid fuelcomponents using standard refining techniques. U.S. Pat. No. 6,143,940discloses a procedure for converting waste plastics into heavy waxcompositions. U.S. Pat. No. 6,150,577 discloses a process of convertingwaste plastics into lubricating oils. EP0620264 discloses a process forproducing lubricating oils from waste or virgin polyolefins by thermallycracking the waste in a fluidized bed to form a waxy product, optionallyusing a hydrotreatment, then catalytically isomerizing and fractionatingto recover a lubricating oil.

Other documents which relate to processes for converting waste plasticinto lubricating oils include U.S. Pat. Nos. 6,288,296; 6,774,272;6,822,126; 7,834,226; 8,088,961; 8,404,912; and 8,696,994; and U.S.Patent Publication Nos. 2019/0161683; 2016/0362609; and 2016/0264885.The foregoing patent documents are incorporated herein by reference intheir entirety.

The current method of chemical recycling via pyrolysis cannot make a bigimpact for the plastics industry. The current pyrolysis operationproduces poor quality fuel components (naphtha and diesel rangeproducts), but the quantity is small enough that these products can beblended into fuel supplies. However, this simple blending cannotcontinue if very large volumes of waste polyethylene and polypropyleneare to be recycled to address environmental issues. The products asproduced from a pyrolysis unit are of too poor quality to be blended inlarge amounts (for example 5-20 vol. % blending) in transportationfuels.

In order to achieve recycling of single use plastics in an industriallysignificant quantity to reduce its environmental impact, more robustprocesses are needed. The improved processes should establish “circulareconomy” for the waste polyethylene and polypropylene plastics where thespent waste plastics are recycled effectively back as starting materialsfor the polymers and high value byproducts.

SUMMARY

Provided is a continuous process for converting waste plastic intorecycle for polyethylene polymerization. The process comprises selectingwaste plastics containing polyethylene and/or polypropylene. These wasteplastics are then passed through a pyrolysis reactor to thermally crackat least a portion of the polyolefin waste and produce a pyrolyzedeffluent. The pyrolyzed effluent is separated into offgas, char and apyrolysis oil and optionally pyrolysis wax comprising a naphtha/dieselfraction and a heavy fraction.

The incorporation of the process with an oil refinery is an importantaspect of the present process, and allows the creation of a circulareconomy with a single use waste plastic such as polyethylene. Thus, thepyrolysis oil and wax, the entire liquid fraction from the pyrolysisunit, is passed to a refinery FCC Feed Pretreater Unit. This unit iseffective in removing sulfur, nitrogen, phosphorus, silica, dienes andmetals that will hurt a FCC unit catalyst performance. Also this unithydrogenates aromatics and improves the liquid yield of the FCC unit.

The pretreated hydrocarbon from the pretreater unit is distilled toproduce LPG, naphtha and heavy fraction. The heavy fraction is sent toan FCC unit for further production of C₃, C₄, FCC gasoline and heavyfraction. From the separation section, clean C₃ LPG fraction containingpropane and propylene is collected. The C₃ stream is a good feed for asteam cracker. The C₃ stream is fed to a steam cracker distillationsection to separate into propane and propylene. Then, propane is fed tothe steam cracker to be converted to pure ethylene.

The refinery will generally have its own hydrocarbon feed flowingthrough the refinery units. The flow volume of pyrolysis oil and waxgenerated from the pyrolysis of waste plastic to the refinery units cancomprise any practical or accommodating volume % of the total flow tothe refinery units. Generally, the flow of the pyrolysis oil and waxgenerated from the waste plastic pyrolysis, for practical reasons, canbe up to about 50 vol. % of the total flow, i.e., the refinery flow andthe pyrolysis flow. In one embodiment, the flow of the pyrolysis oil andwax is an amount up to about 20 vol. % of the total flow.

In another embodiment, a continuous process for converting waste plasticcomprising polyethylene into recycle for polyethylene polymerization isprovided. The process comprises selecting waste plastics containingpolyethylene and polypropylene and then passing the waste plasticsthrough a pyrolysis reactor to thermally crack at least a portion of thepolyolefin waste and produce a pyrolyzed effluent. The pyrolyzedeffluent is separated into offgas, char and a pyrolysis oil comprising anaphtha/diesel fraction and a heavy fraction. The pyrolysis oil and wax,the entire liquid fraction from the pyrolysis unit, is passed to arefinery FCC Feed Pretreater Unit. This unit is effective in removingsulfur, nitrogen, phosphorus, silica, dienes and metals that will hurt aFCC catalyst performance. Also this unit hydrogenates aromatics andimproves the liquid yield of the FCC unit. The pretreated hydrocarbonfrom this unit is distilled to produce LPG, naphtha and heavy fraction.The heavy fraction is sent to the FCC unit for further production of C₃,C₄, FCC gasoline and heavy fraction. From the separation section, cleanC₃ LPG fraction containing propane and propylene is collected. The C₃stream is separated into C₃ paraffin and C₃ olefin fractions. This canbe accomplished by use of a distillation column in the ethylene cracker.The C₃ propane stream is fed to a steam cracker distillation section tobe further converted to pure ethylene.

Among other factors, it has been found that by adding refineryoperations one can upgrade the waste pyrolysis oil to higher valueproducts such as gasoline and diesel. Also, by adding refineryoperations it had been found that clean C₃ can be efficiently andeffectively produced from the waste pyrolysis oil for ultimatepolyethylene polymer production. Positive economics are realized for theoverall process from recycled plastics to a polyethylene product withproduct quality identical to that of virgin polymer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts the current practice of pyrolyzing waste plastics toproduce fuel or wax (base case).

FIG. 2 depicts a present process for establishing a circular economy forwaste plastics in accordance with the present processes.

FIG. 3 depicts the plastic type classification for waste plasticsrecycling.

DETAILED DESCRIPTION

In the present process, provided is a method to recycle wastepolyethylene and/or polypropylene back to virgin polyethylene toestablish the circular economy by combining distinct industrialprocesses. A substantial portion of polyethylene and polypropylenepolymers are used in single use plastics and get discarded after itsuse. The single use plastic waste has become an increasingly importantenvironmental issue. At the moment, there appear to be few options forrecycling polyethylene and polypropylene waste plastics to value-addedchemicals and fuel products. Currently, only a small amount ofpolyethylene/polypropylene is recycled via chemical recycling, whererecycled and cleaned polymer pellets are pyrolyzed in a pyrolysis unitto make fuels (naphtha, diesel), steam cracker feed or slack wax.

Ethylene is the most produced petrochemical building block. Ethylene isproduced in hundreds of millions of tons per year via steam cracking.The steam crackers use either gaseous feedstocks (ethane, propane and/orbutane) or liquid feed stocks (naphtha or gas oil). It is a noncatalyticcracking process operating at very high temperatures, up to 850° C.

Polyethylene is used widely in various consumer and industrial products.Polyethylene is the most common plastic, over 100 million tons ofpolyethylene resins are produced annually. Its primary use is inpackaging (plastic bags, plastic films, geomembranes, containersincluding bottles, etc.). Polyethylene is produced in three main forms:high-density polyethylene (HDPE, ^(˜)0.940-0.965 g/cm⁻³), linearlow-density polyethylene (LLDPE, ^(˜)0.915-0.940 g/cm⁻³) and low-densitypolyethylene (LDPE, (<0.930 g/cm⁻³), with the same chemical formula(C₂H4)_(n) but different molecular structure. HDPE has a low degree ofbranching with short side chains while LDPE has a very high degree ofbranching with long side chains. LLDPE is a substantially linear polymerwith significant numbers of short branches, commonly made bycopolymerization of ethylene with short-chain alpha-olefins.

Low density polyethylene (LDPE) is produced via radical polymerizationat 150−300° C. and very high pressure of 1,000-3,000 atm. The processuses a small amount of oxygen and/or organic peroxide initiator toproduce polymer with about 4,000-40,000 carbon atoms per the averagepolymer molecule, and with many branches. High density polyethylene(HDPE) is manufactured at relatively low pressure (10-80 atm) and80-150° C. temperature in the presence of a catalyst. Ziegler-Nattaorganometallic catalysts (titanium(III) chloride with an aluminum alkyl)and Phillips-type catalysts (chromium(IV) oxide on silica) are typicallyused, and the manufacturing is done via a slurry process using a loopreactor or via a gas phase process with a fluidized bed reactor.Hydrogen is mixed with ethylene to control the chain length of thepolymer. Manufacturing conditions of linear low-density polyethylene(LLDPE) are similar to those of HDPE except copolymerization of ethylenewith short-chain alpha-olefins (1-butene or 1-hexene).

Today, only a small portion of spent polyethylene products is collectedfor recycling efforts due to the inefficiencies discussed above.

FIG. 1 shows a diagram of pyrolysis of waste plastics fuel or wax thatis generally operated in the industry today. As noted above, generally,polyethylene and polypropylene wastes are sorted together 1. The cleanedpolyethylene/polypropylene waste 2 is converted in a pyrolysis unit 3 tooffgas 4 and pyrolysis oil (liquid product). The offgas 4 from thepyrolysis unit is used as fuel to operate the pyrolysis unit. Adistillation unit in the pyrolysis unit separates the pyrolysis oil toproduce naphtha and diesel 5 products which are sold to fuel markets.The heavy pyrolysis oil fraction 6 is recycled back to the pyrolysisunit 3 to maximize the fuel yield. Char 7 is removed from the pyrolysisunit 3. The heavy fraction 6 is rich in long chain, linear hydrocarbons,and is very waxy (i.e., forms paraffinic wax upon cooling to ambienttemperature). Wax can be separated from the heavy fraction 6 and sold tothe wax markets.

The present process converts pyrolyzed polyethylene and/or polypropylenewaste plastic in large quantities by integrating the waste polymerpyrolysis product streams into an oil refinery operation. The resultingprocesses produce the feedstocks for the polymers (for ethylenecracker), high quality gasoline and diesel fuel.

Generally, the present process provides a circular economy forpolyethylene plants. Polyethylene is produced via polymerization of pureethylene. Clean ethylene can be made using a steam cracker. A C₃ streamcan be fed to the steam cracker to create ethylene. The ethylene is thenpolymerized to create polyethylene.

By adding refinery operations to upgrade the waste pyrolysis oil tohigher value products (gasoline and diesel) and to produce clean C₃ LPGfor the steam cracker for ultimate polyethylene polymer production, oneis able to create positive economics for the overall process fromrecycled plastics to polyethylene product with quality identical to thatof the virgin polymer.

A pyrolysis unit produces poor quality products containing contaminants,such as calcium, magnesium, chlorides, nitrogen, sulfur, dienes, andheavy components, which products cannot be used in large quantity forblending in transportation fuels. It has been discovered that by havingthese products go through the refinery units, the contaminants can becaptured in pre-treating units and their negative impacts diminished.The fuel components can be further upgraded with appropriate refineryunits with chemical conversion processes, with the final transportationfuels produced by the integrated process being of higher quality andmeeting the fuels quality requirements. The present process will upgradethe wax into valuable gasoline and diesel. The integrated process willgenerate a much cleaner C₃ stream as steam cracker feedstock forethylene generation and polyethylene production. These large on-specproductions allow “cyclical economy” for the recycle plastics feasible.

The carbon in and out of the refinery operations are “transparent,”meaning that all the molecules from the waste plastic do not necessarilyend up in the exact olefin product cycled back to the polyolefin plants,but are nevertheless assumed as “credit” as the net “green” carbon inand out of the refinery is positive. With these integrated processes,the amount of virgin feeds needed for polyethylene plants will bereduced substantially.

FIG. 2 shows a present integrated process, integrating refineryoperations with recycle for effective polyethylene production. In FIG. 2, mixed waste plastics are sorted together 21. The cleaned waste plastic22 is converted in a pyrolysis unit 23 to offgas 24 and a pyrolysis oil(liquid product) and optionally wax (solid product at ambienttemperature). The offgas 24 from the pyrolysis unit can be used as fuelto operate the pyrolysis unit 23. The pyrolysis oil is separated,generally at an on-site distillation unit in the pyrolysis unit 23, intoa naphtha/diesel fraction 25, and a heavy fraction 26. Char 27 isremoved from the pyrolysis unit 23 after completion of the pyrolysisstep.

The pyrolysis unit can be located near the waste plastics collectionsite, which site could be away from a refinery, near a refinery, orwithin a refinery. If the pyrolysis unit is located away from therefinery, then pyrolysis oil (naphtha/diesel and heavies) can betransferred to the refinery by truck, barge, rail car or pipeline. It ispreferred, however, that the pyrolysis unit is within the waste plasticscollection site or within the refinery.

The preferred starting material for the present process is sorted wasteplastics containing predominantly polyethylene and polypropylene(plastics recycle classification types 2, 4, and 5). The pre-sortedwaste plastics are washed and shredded or pelleted to feed to apyrolysis unit for thermal cracking. FIG. 3 depicts the plastic typeclassification for waste plastics recycling. Classification types 2, 4,and 5 are high density polyethylene, low density polyethylene andpolypropylene, respectively. Any combination of the polyethylene andpolypropylene waste plastics can be used. For the present process, atleast some polyethylene waste plastic is preferred.

Proper sorting of waste plastics is very important in order to minimizecontaminants such as N, Cl, and S. Plastics waste containingpolyethylene terephthalate (plastics recycle classification type 1),polyvinyl chloride (plastics recycle classification type 3) and otherpolymers (plastics recycle classification type 7) need to be sorted outto less than 5%, preferably less than 1% and most preferably less than0.1%. The present process can tolerate a moderate amount of polystyrene(plastics recycle classification type 6). Waste polystyrene needs to besorted out to less than 30%, preferably less than 20% and mostpreferably less than 5%.

Washing of waste plastics removes metal contaminants such as sodium,calcium, magnesium, aluminum, and non-metal contaminants coming fromother waste sources. Non-metal contaminants include contaminants comingfrom the Periodic Table Group IV, such as silica, contaminants fromGroup V, such as phosphorus and nitrogen compounds, contaminants fromGroup VI, such as sulfur compounds, and halide contaminants from GroupVII, such as fluoride, chloride, and iodide. The residual metals,non-metal contaminants, and halides need to be removed to less than 50ppm, preferentially less than 30 ppm and most preferentially to lessthan 5 ppm.

If the washing does not remove the metals, non-metal contaminants, andhalide impurities adequately, then a separate guard bed can be used toremove the metals and non-metal contaminants.

The pyrolyzing is carried out by contacting a plastic material feedstockin a pyrolysis zone at pyrolysis conditions, where at least a portion ofthe feed(s) is cracked, thus forming a pyrolysis zone effluentcomprising primarily olefins and paraffins. Pyrolysis conditions includea temperature of from about 400° C. to about 700° C., preferably fromabout 450° C. to about 650° C. Conventional pyrolysis technology teachesoperating conditions of above-atmospheric pressures. See e.g., U.S. Pat.No. 4,642,401. Additionally, it has been discovered that by adjustingthe pressure downward, the yield of a desired product can be controlled.See, e.g., U.S. Pat. No. 6,150,577. Accordingly, in some embodimentswhere such control is desired, the pyrolysis pressure issub-atmospheric.

FIG. 2 shows a present integrated process where the entire pyrolysis oil(naphtha/diesel fraction and heavy fraction) is sent to a fluidcatalytic cracking (FCC) feed pretreater unit 28. The FCC FeedPretreater typically uses a bimetallic (NiMo or CoMo) alumina catalystin a fixed bed reactor to hydrogenate the feed with H2 gas flow at a660-780° F. reactor temperature and 1,000-2,000 psi pressure. Therefinery FCC Feed Pretreater Unit is effective in removing sulfur,nitrogen, phosphorus, silica, dienes and metals that will hurt the FCCunit catalyst performance. Also this unit hydrogenates aromatics andimproves the liquid yield of the FCC unit.

The refinery will generally have its own hydrocarbon feed flowingthrough the refinery units. The flow volume of pyrolysis oil and waxgenerated from the pyrolysis of waste plastic to the refinery units,here a FCC pretreater and a unit, can comprise any practical oraccommodating volume % of the total flow to the refinery units.Generally, the flow of the pyrolysis oil and wax fraction generated fromthe waste plastic pyrolysis, for practical reasons, can be up to about50 vol. % of the total flow, i.e., the refinery flow and the pyrolysisflow. In one embodiment, the flow of the pyrolysis oil and wax is anamount up to about 20 vol. % of the total flow. In another embodiment,the flow of the pyrolysis oil and wax is an amount up to about 10 vol. %of the total flow. About 20 vol. % has been found to be an amount thatis quite practical in its impact on the refinery while also providingexcellent results and being an amount that can be accommodated. Theamount of pyrolysis oil generated from the pyrolysis can of course becontrolled so that the fraction passed to the refinery units providesthe desired volume % of the flow.

The pretreated hydrocarbon from the feed pretreater unit is distilled toproduce LPG, naphtha and heavy fraction. The heavy fraction is sent to aFCC unit 29 for further production of C₃ 31, C₄ 32, FCC gasoline 33 andheavy fraction 30. The C₄ stream and naphtha from the feed pretreaterunit can be passed to other upgrading processes within the refinery.

The fluid catalytic cracking (FCC) process is widely used in therefining industry for conversion of atmospheric gas oil, vacuum gas oil,atmospheric residues and heavy stocks recovered from other refineryoperations into high-octane gasoline, light fuel oil, heavy fuel oil,olefin-rich light gas (LPG) and coke. FCC uses a high activity zeolitecatalyst to crack the heavy hydrocarbon molecules at a 950-990° F.reactor temperature in a riser with a short contact time of a fewminutes or less. LPG streams containing olefins (propylene, butylene)are commonly upgraded to make alkylate gasoline, or to be used inchemicals manufacturing. A conventional FCC unit is used.

From the separation section, clean C₃ LPG fraction 31 containing propaneand propylene is collected. The C₃ stream is a good feed for a streamcracker. The C₃ stream is fed to a steam cracker 36 distillation sectionto separate into propane and propylene. Then, propane is fed to thesteam cracker to be converted to pure ethylene. The ethylene is thenpolymerized in an ethylene polymerization unit 40. The polyethylene canthen be used to make consumer products 41.

The steam cracker and ethylene polymerization unit is preferably locatednear the refinery so that the feedstock can be transferred via pipeline.For a petrochemical plant located away from the refinery, the feedstockcan be delivered via truck, barge, rail car, or pipeline.

The C₄ olefin stream 32 recovered from the FCC refinery unit can bepassed to various upgrading processes 34 to produce clean gasoline ordiesel 35. The heavy fraction 30 can be passed on to the variousupgrading processes 34 as well to produce more clean gasoline and diesel35. The FCC gasoline 33 collected from the FCC refinery unit 29 can bepooled with clean gasoline produced in the refinery.

The benefits of a circular economy and an effective and efficientrecycling campaign are realized by the present integrated process.

The following examples are provided to further illustrate the presentprocess and its benefits. The examples are meant to be illustrative andnot limiting.

Example 1: Properties of Pyrolysis Oil and Wax From Commercial Sources

Pyrolysis oil and wax samples were obtained from commercial sources andtheir properties are summarized in Table 1. These pyrolysis samples wereprepared from waste plastics containing mostly polyethylene andpolypropylene via thermal decomposition in a pyrolysis reactor at around400-600° C., near atmospheric pressure without any added gas or acatalyst. A pyrolysis unit typically produces gas, liquid oil product,optionally wax product, and char. The pyrolysis unit's overhead gasstream containing thermally cracked hydrocarbon was cooled to collectcondensate as pyrolysis oil (liquid at ambient temperature) and/orpyrolysis wax (solid at ambient temperature). The pyrolysis oil is themain product of the pyrolysis units. Some units produce pyrolysis wax asa separate product in addition to the pyrolysis oil.

TABLE 1 Properties of As-Received Oil and Wax from Pyrolysis of WastePlastics Pyrolysis Oil Pyrolysis Oil Pyrolysis Oil Pyrolysis OilPyrolysis Wax Sample A Sample B Sample C Sample D Sample E SpecificGravity at 60° F. 0.814 0.820 0.774 — 0.828 Simulated Distillation. ° F.87 299 18 86 325 0.5% (Initial Boiling Point)  5% 179 306 129 154 47510% 214 309 156 210 545 30% 322 346 285 304 656 50% 421 447 392 421 73370% 545 585 517 532 798 90% 696 798 663 676 894 95% 772 883 735 743 93999.5% (Final Boiling Point) 942 1079 951 888 1064 Carlo-Erba HydrocarbonAnalysis 87.6 84.21 85.46 85.97 85.94 Carbon, wt % Hydrogen. wt % 12.712.25 14.1 14.0 14.15 Sum of C + H, wt % 100.3 96.46 99.5 100.0 100.1H/C Molar Ratio 1.73 1.75 1.98 1.96 1.98 Bromine Number, g/100 g 49 6040 44 14 Hydrocarbon Type 23.3 22.8 5.1 8.7 13.3 Total Aromatics, vol %Total Olefins & Naphthenes, vol % 39.0 50.2 42.4 38.2 42.1 TotalParaffins, vol % 37.7 27 52.5 53.1 44.6 Contaminants 48 29 7.8 99 6.3Total S, ppm Total N, ppm 751 1410 318 353 237 Total Cl, ppm 113 62 4170 4.7 O in naphtha & distillate, ppm 250 — 574 — — Trace ElementalImpurities <1.1 <0.56 0.6 <0.53 <0.68 Al, ppm Ca, ppm 1.4 11.5 <0.5<0.53 <0.68 Fe, ppm 4.9 11.9 1.6 <1.1 3.1 Mg, ppm <0.51 1.3 <0.52 <0.53<0.68 Na, ppm 2.5 <0.54 <1.1 <2.2 <2.7 Ni, ppm <0.51 <0.54 <0.52 2 <0.68V, ppm <0.51 <0.54 <0.52 4 <0.68 P, ppm 8.2 9.9 <1.6 <2.2 20.2 Si, ppm82.5 49.6 13 17 3.1

ASTM D4052 method was used for specific gravity measurements. Simulatedboiling point distribution curve was obtained using ASTM D2887 method.Carlo-Erba analysis for carbon and hydrogen was based on ASTM D5291method. Bromine number measurement was based on ASTM D1159 method.Hydrocarbon-type analysis was done using a high resolution magnetic massspectrometer using the magnet scanned from 40 to 500 Daltons. Totalsulfur was determined using XRF per ASTM D2622 method. The nitrogen wasdetermined using a modified ASTM D5762 method using chemiluminescencedetection. The total chloride content was measured using combustion ionchromatography instrument using modified ASTM 7359 method. The oxygencontent in naphtha and distillate boiling range was estimated using GCby GC/MS measurements with electron ionization detector for m/Z range of29-500. Trace metal and non-metal elements in oil were determined usinginductively coupled plasma-atomic emission spectrometry (ICP-AES).

Industrial pyrolysis process of sorted plastics, sourced predominantlyfrom polyethylene and polypropylene waste, produced quality hydrocarbonstreams with specific gravity ranging 0.7 to 0.9, and a boiling rangefrom 18 to 1100° F. as in pyrolysis oil or pyrolysis wax.

The pyrolysis product is rather pure hydrocarbon made of mostly carbonand hydrogen. The hydrogen to carbon molar ratio varies from 1.7 to near2.0. The Bromine Number is in the range of 14 through 60 indicatingvarying degrees of unsaturation coming from olefins and aromatics. Thearomatic content is in the range of 5 to 23 volume % with a higherseverity unit producing more aromatics. Depending on the processconditions of the pyrolysis unit, the pyrolysis products show paraffiniccontent ranging from mid-20 vol. % to mid-50 vol. %. The pyrolysisproduct contains a substantial amount of olefins. Samples A and B,pyrolysis oil produced under more severe conditions such as higherpyrolysis temperature and/or longer residence time, contain higheraromatic and lower paraffinic components, resulting H/C molar ratio ofaround 1.7 and high Bromine Number of 50-60. Samples C and D wereproduced at less severe conditions, and the pyrolysis oils are moreparaffinic, resulting H/C molar ratio of close to 2.0 and Bromine Numberaround 40. Sample E, pyrolysis wax, is mostly paraffinic, saturatedhydrocarbon with a substantial amount of normal hydrocarbons (as opposedto branched hydrocarbons) with low Bromine Number of only 14.

The following Examples 2 through 5 show the evaluation of waste plasticspyrolysis oil for transportation fuel.

Example 2: Fractionation of Pyrolysis Oil for Evaluation asTransportation Fuel

Sample D was distilled to produce hydrocarbon cuts representing gasoline(350° F.⁻), jet (350-572° F.), diesel (572-700° F.) and the heavy (700°r) fractions. Table 2 summarizes the boiling point distribution andimpurity distributions among the distilled product fractions.

TABLE 2 Distillation of Pyrolysis Oil into Fuel Fractions Sample IDSample D Sample F Sample G Sample H Sample I Intended Fraction GasolineCut Jet Cut Diesel Cut Unconverted Cut Point Target, ° F. 350⁻ 350-572572-700 700⁺ Distillation Actual Yields, wt % 37.2 38.0 15.0 9.3Simulated Distillation, F IBP (0.5 wt %) 86 27 299 539 640  5 wt % 15498 345 557 684 10 wt % 210 147 365 574 696 30 wt % 304 222 416 597 72750 wt % 421 270 457 619 758 70 wt % 532 291 492 644 808 90 wt % 676 337546 674 898 95 wt % 743 347 554 683 953 FBP (99.5 wt %) 888 385 591 7111140 Total S, ppm 99 52 35 80 320 Total N, ppm 353 215 556 232 467 TotalCl, ppm 70 181 27 12 13

Example 3: Evaluation of Pyrolysis Oil Cut for Gasoline Fuel

Sample F, a pyrolysis oil cut for gasoline fuel boiling range, wasevaluated to assess its potential to use as gasoline fuel. Sample F hasthe carbon number range of C₅-C₁₂, typical of the gasoline fuel.

Due to the olefinic nature of the pyrolysis oil, oxidation stability(ASTM D525) and gum forming tendency (ASTM D381) were identified as themost critical properties to examine. Research octane number (RON) andmotor octane number (MON) are also the critical properties for engineperformance. The RON and MON values were estimated from detailedhydrocarbon GC analysis.

TABLE 3 Evaluation of Pyrolysis Oil Naphtha Fraction for Gasoline FuelOxidation Washed Stability, Gum, mg/1 min 00 mL RON MON Sample F 90 5.071.4 67.7 Reference gasoline >1440 1 95.8 86.2 4/96 vol. % Blend ofSample >1440 2.0 94.5 85.1 F with reference gasoline 15/85 vol. % Blendof Sample >1440 2.2 91.8 83.1 F with reference gasoline

Sample F, a pyrolysis oil cut for gasoline fuel boiling range, cannot beused by itself as automotive gasoline fuel due to its poor quality. Thegasoline fraction from the pyrolysis oil showed very poor oxidationstability in that Sample F failed only after 90 min compared to thetarget stability of longer than 1440 minutes. The pyrolysis gasolineexceeded the wash gum target of 4 mg/100 mL suggesting severe gumforming tendency. The pyrolysis gasoline has poor octane numberscompared to the reference gasoline. A premium unleaded gasoline was usedas the reference gasoline.

We also examined the potential of blending of the pyrolysis gasoline cutfor a limited amount to the reference gasoline. Our study showed thatpossibly up to 15 volume % of Sample F can be blended to the refinerygasoline while still meeting the fuels property targets. By integratingthe pyrolysis gasoline product with a refinery fuel, the overall productquality can be maintained.

These results indicate that the as-produced gasoline fraction ofpyrolysis oil has limited utility as gasoline fuel. Upgrading in arefinery unit is preferred to convert this gasoline fraction of thepyrolysis oil into hydrocarbon that meets the gasoline fuel propertytargets.

Example 4: Evaluation of Pyrolysis Oil Cut for Jet Fuel

Sample G, a pyrolysis oil cut for jet fuel boiling range, was evaluatedto assess its potential to use as jet fuel. Sample G has the carbonnumber range of C₉-C₁₈, typical of the jet fuel.

Due to the olefinic nature of the pyrolysis oil, jet fuel thermaloxidation test (D3241) was considered as the most critical test. Thepyrolysis oil jet cut as-is, Sample G, had only 36 minutes of oxidationstability suggesting the pure pyrolysis jet cut is unsuitable for use asjet fuel.

We prepared a 5 volume % blend of pyrolysis jet cut (Sample G) withrefinery produced jet. The blend still failed for the jet fuel oxidationtest as shown in Table 4.

TABLE 4 Evaluation of Pyrolysis Oil Jet Fraction for Jet Fuel Jet FuelThermal Oxidation Test Reference jet fuel Passed 5/95 vol % Blend ofSample G Failed with reference jet fuel

These results indicate that the as-produced jet fraction of pyrolysisoil is completely unsuitable for jet fuel, and upgrading in a refineryunit is required to convert this jet fraction of the pyrolysis oil intohydrocarbon that meets the jet fuel property targets.

Example 5: Evaluation of Pyrolysis Oil Cut for Diesel Fuel

Sample H, a pyrolysis oil cut for diesel fuel boiling range, wasevaluated to assess its potential to use as diesel fuel. Sample H hasthe carbon number range of C₁₄-C₂₄, typical of the diesel fuel.

Sample H contains a substantial amount of normal hydrocarbons. Sincenormal hydrocarbons tends to exhibit waxy characteristics, cold flowproperties such as pour point (ASTM D5950-14) and cloud points (ASTMD5773) were considered as the most critical tests.

We prepared two blends at 10 and 20 volume % of Sample H with refineryproduced diesel fuel. However, both blends still failed for the targetpour point of less than −17.8° C. (0° F.) pour points.

TABLE 5 Evaluation of Pyrolysis Oil Diesel Fraction for Diesel FuelCloud Pour Pour Point (° C.) Point (° C.) Point Test Reference dieselfuel −17.1 −19.0 Passed 10/90 vol. % Blend −11.1 −12.0 Failed of SampleH with reference diesel fuel 20/80 vol. % Blend −5.5 −7.0 Failed ofSample H with reference diesel fuel

These results indicate that the pyrolysis oil as-is is completelyunsuitable for diesel fuel, and upgrading in a refinery unit is requiredto covert the diesel fraction of pyrolysis oil into hydrocarbon thatmeets the diesel fuel property targets.

Examples 6: Coprocessing of Pyrolysis Product to FCC Pretreater UnitFollowed by FCC Unit

Results from Table 1 showed that industrial pyrolysis process of sortedplastics, sourced predominantly from polyethylene and polypropylenewaste, produced quality pyrolysis oil or pyrolysis wax made of mostlycarbon and hydrogen. With good sorting and efficient pyrolysis unitoperation, the nitrogen and sulfur impurities are at low enough levelsthat a modern refinery can handle cofeeding of pyrolysis feedstocks totheir processing units with no detrimental impacts.

However, some pyrolysis oils or wax may still contain high amounts ofmetals (Ca, Fe, Mg) and other non-metals (N, S, P, Si, Cl, O) that couldnegatively affect the performance of conversion units in a refinery. Forpyrolysis products with high impurity levels are preferentially fed to aFCC feed treater unit before the FCC unit so that bulk of impurities areremoved effectively by the pretreater.

By feeding the entire pyrolysis feedstock to a FCC pretreater unitbefore the FCC unit, as shown in FIG. 2 , the impurity levels arelowered significantly. The hydrotreated pyrolysis oil and wax are thenconverted in the FCC into offgas, LPG paraffins and olefins, FCCgasoline and heavy hydrocarbon components. The FCC gasoline is avaluable gasoline blending component. The heavy fractions, light cycleoil (LCO) and heavy cycle oil (HCO) are converted further in thesubsequent conversion units including jet hydrotreating unit, dieselhydrotreating unit, hydrocracking unit and/or coker unit to make moregasoline, jet, and diesel fuel with satisfactory product properties. TheLPG paraffins and olefins are either processed further in an alkylationunit or in part used for petrochemicals production with a recyclecontent.

The following Example 7 shows how the FCC feed pretreater can reduce theimpurities in pyrolysis products. The reduction of impurities willextend the FCC catalyst life and lower the FCC catalyst consumption.

Example 7: Hydrotreating of Pyrolysis Product for Impurity Removal

To study the effectiveness of hydrotreating of waste plastics pyrolysisproduct for impurity removal, Sample E, crude wax from the pyrolysisprocess, was hydrogenated in a continuous fixed bed unit containing aNiMo/Alumina catalyst at 600° F. reactor temperature and 600 psigpressure. A liquid feed flow rate of 1.0 hr⁻¹ relative to the catalystbed volume and Hz/Hydrocarbon flow rate of 2500 scf/bbl were used toproduce the hydrogenated product, Sample J. The results are summarizedbelow in Table 6.

TABLE 6 Hydrogenation of Pyrolysis Wax Before Cofeeding to FCC Sample ESample J As- Hydrogenated received Waxy Fraction Waxy (hydrogenatedDescription Fraction Sample E) Simulated Distillation. ° F. 0.5%(Initial Boiling Point) 325 331  5% 475 488 10% 545 548 30% 656 657 50%733 733 70% 798 797 90% 894 892 95% 939 936 99.5% (Final Boiling Point)1064 1055 Bromine Number, g/100 g 14 0.14 Contaminants 6.3 Belowdetection Total S, ppm Total N, ppm 237 <0.3 Total Cl, ppm 4.7 Belowdetection Trace Elemental Impurities Fe, ppm 3.1 <1.1 P, ppm 20.2 <2.2Si, ppm 3.1 <0.55 Color & physical state at Light brown solid Whitesolid ambient temperature

Hydrogenation of pyrolysis wax, Sample E, produced excellent qualityhydrogenated wax, Sample J. All trace impurities are completely removedby the hydrogenation process in that Sample J has no measurableimpurities that could harm the FCC catalyst. This example shows thathigh quality, pure paraffinic hydrocarbon can be produced effectivelyfrom waste plastics containing predominately polyethylene andpolypropylene, and that mild hydrogenation is a very effective method topurify the waste plastic derived oil and wax.

The following Examples 8 and 9 demonstrate the conversion of wasteplastics pyrolysis product into quality transportation fuel in arefinery conversion unit, using a FCC unit as an example.

Example 8: Conversion of Pyrolysis Oil in FCC

To study the impact of coprocessing of waste plastics pyrolysis oil toFCC, series of laboratory tests were carried out with Samples A and C.Vacuum gas oil (VGO) is the typical feed for FCC. FCC performances of 20volume % blend of pyrolysis oil with VGO and pure pyrolysis oil werecompared with that of the pure VGO feed.

The FCC experiments were carried out on a Model C ACE (advanced crackingevaluation) unit fabricated by Kayser Technology Inc. using regeneratedequilibrium catalyst (Ecat) from a refinery. The reactor was a fixedfluidized reactor using N2 as fluidization gas. Catalytic crackingexperiments were carried out at the atmospheric pressure and 900° F.reactor temperature. The cat/oil ratio was varied between 5 to 8 byvarying the amount of the catalyst. A gas product was collected andanalyzed using a refinery gas analyzer (RGA), equipped with GC with FIDdetector. In-situ regeneration of a spent catalyst was carried out inthe presence of air at 1300° F., and the regeneration flue gas waspassed through a LECO unit to determine the coke yield. A liquid productwas weighted and analyzed in a GC for simulated distillation (D2887) andC₅ ⁻ composition analysis. With a material balance, the yields of coke,dry gas components, LPG components, gasoline (C5-430° F.), light cycleoil (LCO, 430-650° F.) and heavy cycle oil (HCO, 650° F.⁺) weredetermined. The results are summarized below in Table 7.

TABLE 7 Evaluation of Pyrolysis Oil Cofeeding to FCC 20/80 20/80 vol %vol % blend, blend, 100% 100% 100% Sample Sample Sample Sample Feed VGOA/VGO C/VGO A C Cat/Oil, wt/wt 6.0 6.0 6.0 6.0 6.0 Conversion, wt %*81.3 83.15 83.09 76.1 78.82 WLP Impurity** 81 76 62 54 67 Total O, ppmTotal N, ppm 27 30 33 50 21 Yields Coke, wt % 4.45 4.35 4.20 3.56 2.90Total Dry Gas, 2.08 1.96 1.93 1.55 1.43 wt % Hydrogen 0.16 0.12 0.120.05 0.04 Methane 0.68 0.65 0.64 0.50 0.46 Ethane 0.44 0.43 0.41 0.330.28 Ethylene 0.76 0.74 0.72 0.63 0.61 Total LPG, wt % 21.25 21.08 21.5020.17 24.40 Propane 1.78 1.76 1.72 1.47 1.53 Propylene 5.53 5.51 5.565.57 6.75 n-Butane 1.56 1.56 1.54 1.29 1.34 Isobutane 6.61 6.48 6.645.43 6.61 C4 olefins 5.77 5.77 6.04 6.41 8.16 Gasoline, wt % 53.53 55.7555.46 62.53 61.75 LCO, wt % 12.89 12.23 11.93 10.37 8.03 HCO, wt % 5.814.63 4.98 1.82 1.50 Octane 88.05 84.57 82.79 73.75 75.41 Number****Conversion - conversion of 430° F⁺. fraction to 430° F⁻. **Impuritylevel of N and O in whole liquid product in fuels boiling range by GC xGC, ppm ***Octane number, (R + M)/2, was estimated from detailedhydrocarbon GC of FCC gasoline.

The results in Table 7 show that up to 20 volume % cofeeding ofpyrolysis oil only makes very slight changes in the FCC unit performanceindicating coprocessing of pyrolysis oil up to 20% is readily feasible.The 20 volume % blending of Sample A or Sample C led to very slightreduction of coke and dry gas yields, slight increase in gasoline yieldand slight decrease in LCO and HCO, which are favorable in mostsituations. With paraffinic nature of pyrolysis oil, the 20% blends of Aand C lowered the Octane number by about 3-5 numbers. With refineryoperational flexibility, these octane number debits can be compensatedwith blending or feeding location adjustments.

The FCC unit cracks the pyrolysis oil info fuel range hydrocarbons,reduces impurities, and isomerize n-paraffins to isoparaffins. All thesechemistry will improve the fuel properties of the pyrolysis oil and wax.By cofeeding the pyrolysis oil through the FCC process unit with azeolite catalyst, the oxygen and nitrogen impurities in the fuel rangewere reduced substantially, from about 300-1400 ppm N to about 30 ppm Nand from about 250-540 ppm 0 to about 60-80 ppm 0. The hydrocarboncomposition of all these cofeeding products are well within the typicalFCC gasoline range.

The FCC runs of 100% pyrolysis oil showed substantial debits of Octanenumbers by about 13-14 numbers. This shows that coprocessing ofpyrolysis oil is preferred over processing of pure 100% pyrolysis oil.

Example 9: Coprocessing of Pyrolysis Wax in FCC

To study the impact of coprocessing of waste plastics pyrolysis wax toFCC, series of laboratory tests were carried out with Sample E and VGO.FCC performances of 20% blend of pyrolysis wax with VGO and purepyrolysis wax were compared with that of the pure VGO feed, similar toExample 8. The results are summarized below in Table 8.

TABLE 7 Evaluation of Pyrolysis Wax Cofeeding to FCC 100% 20/80 vol %blend, 100% Feed VGO Sample E/ VGO Sample E Cat/Oil, wt/wt 6.5 6.5 6.5Conversion, wt %* 82.75 84.17 91.31 Yields Coke, wt % 4.78 4.76 4.26Total Dry Gas, wt % 2.11 2.05 1.79 Hydrogen 0.16 0.14 0.07 Methane 0.690.67 0.58 Ethane 0.44 0.43 0.37 Ethylene 0.78 0.77 0.73 Total LPG, wt %21.71 23.15 31.79 Propane 1.87 1.93 2.28 Propylene 5.54 5.98 8.59n-Butane 1.65 1.74 2.15 Isobutane 6.91 7.25 8.88 C4 olefins 5.74 6.259.89 Gasoline, wt % 54.16 54.21 53.47 LCO, wt % 12.42 11.59 6.71 HCO, wt% 4.83 4.24 1.99 Octane Number** 89.95 88.38 83.52 *Conversion -conversion of 430° F⁺. fraction to 430° F⁻. **Octane number, (R + M)/2,was estimated from detailed hydrocarbon GC of FCC gasoline.

The results in Table 8 shows that up to 20 volume % cofeeding ofpyrolysis wax only makes very slight changes in the FCC unit performanceindicating coprocessing of pyrolysis wax up to 20% is readily feasible.The 20 volume % blending of Sample E led to very slight reduction to nochange of coke and dry gas yields, noticeable increase in LPG olefinyield, very slight increase in gasoline yield and slight decrease in LCOand HCO, which are all favorable in most situations. With paraffinicnature of pyrolysis wax, the 20% blend of Sample E lowered the Octanenumber slightly by 1.5 number. With refinery blending flexibility, thisoctane number debit can be easily compensated with minor blendingadjustments.

The FCC run of 100% pyrolysis wax showed substantial increase inconversion, and debit of the Octane number by 6. This shows thatcoprocessing of pyrolysis wax is preferred over processing of 100%pyrolysis wax.

Example 10: Feeding of LPG Olefins from FCC Unit, Which CoprocessedWaste Plastics Pyrolysis Product, to Refinery Alkylation Unit

Cofeeding of pyrolysis oil and/or wax to a FCC unit, as shown inExamples 8 and 9, produces a substantial amount of C₃-C₅ olefins with arecycle content. The C₄ only or C₄-C₅ stream containing recycled olefinsis separated from FCC light-end recovery units, and then fed to analkylation unit or blended into gasoline pool. Reaction of LPG olefinsand isobutane in the alkylation reactor produces propane, butane andalkylate gasoline with recycle contents. Alkylate gasoline and butaneare valuable gasoline blending components. The C₃ LPG stream from theFCC unit is a valuable feedstock for a steam cracker.

Example 11: Feeding of Recycled C₃ LPG Stream to Steam Cracker forEthylene Production, Followed by Productions of Polyethylene Resin andPolyethylene Consumer Products

The C₃ LPG stream containing propane and propylene, produced viacofeeding of pyrolysis products to a FCC unit, is separated and fed to asteam cracker for production of ethylene with a recycle content, asshown in FIG. 2 . The ethylene is then processed to a polymerizationunit to produce polyethylene polymer resin containing somerecycled-polyethylene/polypropylene derived materials while the qualityof the newly produced polyethylene is indistinguishable to the virginpolyethylene made entirely from virgin petroleum resources. Thepolyethylene resin with the recycled material is then further processedto produce various polyethylene products to fit the needs of consumerproducts. These polyethylene consumer products now contains chemicallyrecycled, circular polymer while qualities of the polyethylene consumerproducts are indistinguishable from those made entirely from virginpolyethylene polymer. These chemically recycled polymer products aredifferent from the mechanically recycled polymer products whosequalities are inferior to the polymer products made from virginpolymers.

The foregoing examples together clearly show a new effective way torecycle a large quantity of polyethylene and polypropylene derived wasteplastics via chemical recycling through pyrolysis followed by cofeedingof the pyrolysis products in a refinery via efficient integration. Thisintegration allows quality fuels and circular polymer productions.

As used in this disclosure the word “comprises” or “comprising” isintended as an open-ended transition meaning the inclusion of the namedelements, but not necessarily excluding other unnamed elements. Thephrase “consists essentially of” or “consisting essentially of” isintended to mean the exclusion of other elements of any essentialsignificance to the composition. The phrase “consisting of” or “consistsof” is intended as a transition meaning the exclusion of all but therecited elements with the exception of only minor traces of impurities.

All patents and publications referenced herein are hereby incorporatedby reference to the extent not inconsistent herewith. It will beunderstood that certain of the above-described structures, functions,and operations of the above-described embodiments are not necessary topractice the present invention and are included in the descriptionsimply for completeness of an exemplary embodiment or embodiments. Inaddition, it will be understood that specific structures, functions, andoperations set forth in the above-described referenced patents andpublications can be practiced in conjunction with the present invention,but they are not essential to its practice. It is therefore to beunderstood that the invention may be practiced otherwise that asspecifically described without actually departing from the spirit andscope of the present invention as defined by the appended claims.

What is claimed is:
 1. A continuous process for converting waste plastic into recycle for ethylene production comprising: (a) selecting waste plastics containing polyethylene and/or polypropylene; (b) passing the waste plastics from (a) through a pyrolysis reactor to thermally crack at least a portion of the polyethylene and/or polypropylene and produce a pyrolyzed effluent; (c) separating the pyrolyzed effluent into offgas, char and a pyrolysis oil and optionally wax comprising a naphtha/diesel fraction and a heavy fraction; (d) passing the pyrolysis oil and wax from (c) to a refinery FCC feed pretreater unit; (e) recovering a pretreated pyrolysis oil and wax from the FCC feed pretreater unit and passing it to a refinery FCC unit, wherein the volume flow of the pretreated pyrolysis oil and wax to the FCC unit comprises up to but no more than 50 volume % of the total hydrocarbon flow to the FCC unit, wherein the remaining hydrocarbon flow to the refinery FCC unit comprises vacuum gas oil (VGO); (f) recovering a liquid petroleum gas C₃ olefin/paraffin mixture fraction and a gasoline fraction from the refinery FCC unit; and (g) passing the liquid petroleum gas C3 olefin/paraffin mixture fraction to a steam cracker for ethylene production.
 2. The process of claim 1, wherein a C4 stream and a heavy fraction are recovered from the refinery FCC unit.
 3. The process of claim 1, wherein ethylene produced in (g) is subsequently polymerized.
 4. The process of claim 3, wherein polyethylene products are prepared from the polymerized ethylene.
 5. The process of claim 1, wherein the gasoline fraction recovered from the refinery FCC unit is sent to a gasoline blending pool.
 6. The process of claim 5, wherein the amount of gasoline produced by the refinery FCC unit is increased with recycled pyrolysis oil.
 7. The process of claim 2, wherein the heavy fraction and C₄ stream recovered from the refinery FCC unit are sent to refinery units for upgrading into gasoline and diesel fuels.
 8. The process of claim 1, wherein sulfur, nitrogen, phosphorus, silica, dienes and metal contaminants are removed from the recovered pyrolysis oil of step (c) by the FCC feed pretreater unit before the oil is passed to the FCC unit in (e).
 9. The process of claim 1, wherein the waste plastics passed from (a) contain less than 50 ppm halides.
 10. The process of claim 1, wherein the waste plastics contain less than 5 wt. % polyethylene terephthalate and polyvinyl chloride.
 11. The process of claim 1, wherein the waste plastics selected in (a) are from plastics classification group 2, 4, and/or
 5. 12. A continuous process for converting waste plastic into recycle for ethylene production comprising: (a) selecting waste plastics containing polyethylene and/or polypropylene; (b) passing the waste plastics from (a) through a pyrolysis reactor to thermally crack at least a portion of the polyethylene and/or polypropylene and produce a pyrolyzed effluent; (c) separating the pyrolyzed effluent into off gas, char and a pyrolysis oil and optionally pyrolysis wax comprising a naphtha/diesel fraction and a heavy fraction; (d) passing the pyrolysis oil and wax from (c) to a refinery FCC feed pretreater unit; (e) recovering a pretreated pyrolysis oil and wax from the FCC feed pretreater unit and passing it to a refinery FCC unit, wherein the volume flow of the pretreated pyrolysis oil and wax to the FCC unit comprises up to but no more than 50 volume % of the total hydrocarbon flow to the FCC unit, wherein the remaining hydrocarbon flow to the refinery FCC unit comprises vacuum gas oil (VGO); (f) recovering a liquid petroleum gas C3 olefin/paraffin mixture fraction and a gasoline fraction from the refinery FCC unit; (g) separating the C3 paraffin and C3 olefin into different fractions; and (h) passing the C3 paraffin fraction to a steam cracker for ethylene production.
 13. The process of claim 12, wherein a C4 stream and a heavy fraction are recovered from the refinery FCC unit.
 14. The process of claim 12, wherein the gasoline fraction recovered from the refinery FCC unit is sent to a gasoline blending pool.
 15. The process of claim 13, wherein the heavy fraction and C₄ stream recovered from the refinery FCC unit are sent to refinery units for upgrading into gasoline and diesel fuels.
 16. The process of claim 13, wherein the amount of gasoline produced by the refinery FCC unit is increased with recycled pyrolysis oil.
 17. The process of claim 12, wherein sulfur, nitrogen, phosphorus silica, dienes, and metal contaminants are removed from the recovered pyrolysis oil of step (c) by the FCC feed pretreater unit before the oil and wax is passed to the FCC unit in (e).
 18. The process of claim 12, wherein the waste plastics selected in (a) are from plastics classification group 2, 4, and/or
 5. 19. The process of claim 12, wherein the ethylene produced in (h) is subsequently polymerized.
 20. The process of claim 19, wherein polyethylene products are prepared from the polymerized ethylene. 